In the past, many types of debris removal lift means have been designed for filter bars. Prior art filters utilized debris removal lift means that were disengaged rearward from the filter bars, or held the distal end of the teeth forward of the front face of the filters during the return or downward portion of the cyclic movement, or required additional sets of filter bars. In the past lifting mechanisms were positioned upstream of the filter bars in some designs and downstream of the filter bars in others. Such lift mechanisms often jammed debris between the teeth and the filter bars, or jammed the teeth and the filter bars. When the debris or the teeth are jammed in the filter bar the filter system is inoperative until external means are used to clear the jam.
The lifting mechanisms also govern the minimal usable dimensions between each vertical filter. This dimension is relatively large due to the normal disengagement, in prior art, of the teeth from between the filter bars on the return half of the cyclic movement of the lift mechanism from its uppermost position to its lowermost start position, and to periodic failure of the teeth to properly align with the respective openings between the filter bars.